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This article describes micro‐ and nanostructural, mechanical, and thermal properties of nanocomposites based on polyvinyl chloride (PVC) and graphene nanoplatelets (GNP). The primary objective of this study was to extend restricted application area of PVC due to its low thermal stability and limited mechanical properties. GNP‐filled PVC nanocomposites were prepared (0, 0.1, 0.3, 0.5, and 1.0 wt%) by colloidal blending method and characterized in detail. The highest value of the tensile strength 13.73 MPa (an increase of 58%) and the highest value of microhardness 83.42 MPa (an increase of 82%) were obtained with GNP loading content of 0.5 wt% compared neat PVC. The mechanical properties started to decrease at loading higher than 0.5 wt%; however, the thermal properties continued to increase. The differential scanning calorimetry and Fourier transform infrared analysis results of this nanocomposite confirmed that the increase in glass transition temperature from 34.99°C to 44.36°C and the decrease in the height of functional groups peaks proved to prevented segmental relaxation and intermolecular vibrations of PVC, respectively. Thermogravimetric analysis results were showed that the percentage of carbonaceous residue increased to 15.77% by increasing the GNP content from 0.1 to 0.5 wt%. As a result, the best GNP loading was at 0.5 wt% for PVC/GNP nanocomposites where mechanical and thermal properties of PVC/GNP were both enhanced.

Ultra-high molecular weight polyethylene (UHMWPE) has been broadly utilized in hip and knee artificial implant due to its low friction coefficient, high wear resistance and good biocompatibility. However, some disadvantage properties such as low young's modulus and low load bearing, anti-fatigue capacity limit application areas and wear debris of UHMWPE components cause implant failure. For this reason, reduced graphene oxide (RGO) filler was produced by green synthesis with vitamin C and the influences of RGO filler content on the tribological performance under distilled water lubrication condition were investigated and had been correlated with microstructure. RGO filled UHMWPE biocomposites were fabricated by firstly liquid phase ultrasonic mixing and then hot press molding. The characterization and experiment results revealed that the wear behavior of UHMWPE/RGO biocomposites were not only affected by the lubricant and binder properties of RGO, but also restricted by the content of RGO filler. The RGO filled UHMWPE biocomposites exhibited a lower wear rate and friction coefficient in comparison to the unfilled UHMWPE. The biocomposite with 0.7 wt% of RGO showed good interfacial bonding strength and excellent wear resistance. Furthermore, fatigue wear tracks reduced significantly on the same biocomposite surface. High crystallite size and microhardness value of UHMWPE/RGO-0.7 biocomposite was caused destroy the tribofilm formed on the Al 2 O 3 counterface.

The adsorption of methylene blue (MB) on graphene‐based adsorbents was tested through the batch experimental method. Two types of graphene‐based adsorbents as graphene oxide (GO) and reduced graphene oxide (RGO) were compared to investigate the best adsorbent for MB removal. So that optimizing the MB removal for the selected type of graphene‐based adsorbent, the diverse experimental factors, as pH (2–10), contact time (0–1440 min), adsorbent dosage (0.5–2 g/L), and initial MB concentration (25–400 mg/L) were analyzed. The conclusions indicated that the MB removal rised with an increase in the initial concentration of the MB and so rises in the amount of adsorbent used and initial pH. Maximum dye removal was calculated as 99.11% at optimal conditions after 240 min. Adsorption data were compiled by the Langmuir isotherm (R2: 0.999) and pseudo‐second‐order kinetic models (R2: 0.999). The Langmuir isotherm model accepted that the homogeneous surface of the GO adsorbent covering with a single layer. And the adsorption energy was calculated as 9.38 kJ mol−1 according to the D‐R model indicating the chemical adsorption occurred. The results show that GO could be utilized for the treatment of dye‐contaminated aqueous solutions effectively.

In this study, a simple and green chemistry approach is described for the preparation of reduced graphene oxide (RGO). To this aim, we used a novel reducing agent (vitamin C) for the synthesis of RGO. The GO was reduced at different weight ratios of vitamin C:GO (1:1, 1.5:1 and 2:1). The XRD, FTIR and EDS results showed the deoxygenation of GO due to the loss of hydroxyl, carbonyl, and epoxy groups. The thermal stability of the GO was lower than those of all the RGO powders, and the BET surface area of the GO was much lower than those of all the RGO powders. The results showed that the structural and thermal properties of RGO powders depend on the ratio of vitamin C:GO. When the ratio is 1:1, the RGO powder has the best thermal stability, and the highest BET surface area (m2g−1) was found to be a 2:1 ratio.